Interpretive Summary: The United States Department of Agriculture (USDA) - Agricultural Research Service (ARS) - National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon, preserves more than 1500 blueberry relatives. This collection represents 68 species originating from 34 countries. In this study, molecular markers were examined by statistical tools to assess the diversity of blueberries and determine a unique fingerprint for each of the blueberries in the collection. Much more diversity was present in wild species than in the cultivated blueberries. Within the cultivated blueberries, both the northern and the southern types had an equivalent amount of diversity, though they were distinctly different. We were able to distinguish between 69 blueberries, including 13 wild genotypes and 56 commercial kinds, using 28 molecular markers. We have added our data and images of the blueberry fingerprints to the publicly accessible database, Germplasm Resources Information Network (GRIN) at http://www.ars-grin.gov/cgi-bin/npgs/html/eval.pl?492548. This information, once it is further expanded, can help scientists determine species relationships and nurserymen or growers verify the identity of questionable types.

Technical Abstract:
Twenty EST-SSR and 8 genomic microsatellite loci were used to determine genetic diversity in 69 Vaccinium corymbosum L. accessions consisting of 13 wild accessions and 56 cultivars (one half-high, 18 southern highbush and 37 northern highbush). Historical and modern (patented) cultivars were represented. A decrease in genetic diversity parameters between wild and cultivated types was observed, as measured by the total number of alleles, the number of unique alleles, and Shannon’s index. The number of alleles and Shannon’s index did not differ between cultivated northern and southern highbush accessions, so that substantial genetic diversity remains within the cultivated gene pool. Genetic relationships based on microsatellites corresponded with known pedigree information. Clustering of genetic distances using Neighbor Joining or Principal Component analyses identified three clusters: a mostly wild, a southern highbush and a northern highbush group. Unique fingerprints were obtained for the analyzed accessions. These genetic profiles were deposited as tabled data and voucher images on the publicly accessible database, US Department of Agriculture, Agricultural Research Service’s Germplasm Resources Information Network (GRIN) at
http://www.ars-grin.gov/cgi-bin/npgs/html/eval.pl?492548 . This data is searchable on blueberry cultivar name or plant identification (PI) number. Future application of these blueberry microsatellites could include the determination of species relationships within the genus, genetic diversity estimates in botanical collections, and identity confirmation of unknown or questionable genotypes.